I also have an embroidery collection but a lot of that is on the external hard drive of my computer. I do have over 300 threads with another 45 coming from the States.
I don't feel in the least guilty as I make lots of charity quilts plus this is my reward for quitting smoking 18 months ago.
Maybe if I stopped buying fabric and thread as well as designs I could build an extra room and get my bedroom back. In the meantime I'll just enjoy. As DH says "if it makes you happy, just do it"